1. \(\left( { - 12,245} \right) + \left( { - 8,235} \right)\)
2. \(\left( { - 8,451} \right) + 9,79\)
3. \(\left( { - 11,254} \right) - \left( { - 7,35} \right)\)
i, \(\left(x-1\right)\left(x+3\right)-\left(x-1\right)\left(2x+1\right)=0\)
k, \(\left(x+2\right)\left(x+1\right)-\left(x-3\right)\left(x+2\right)=0\)
l, \(\left(x-2\right)\left(x+3\right)=\left(x-2\right)\left(2x+5\right)\)
\(\left(x-1\right)\left(-x+2\right)=0\Leftrightarrow x=1;x=2\)
\(\left(x+2\right)\left(x+1-x+3\right)=0\Leftrightarrow x=-2\)
\(\left(x-2\right)\left(x+3\right)-\left(x-2\right)\left(2x+5\right)=0\Leftrightarrow\left(x-2\right)\left(-x-2\right)=0\Leftrightarrow x=-2;x=2\)
\(i,\left(x-1\right)\left(x+3\right)-\left(x-1\right)\left(2x+1\right)=0\\ \Leftrightarrow\left(x-1\right)\left(x+3-2x-1\right)=0\\ \Leftrightarrow\left(x-1\right)\left(-x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=1\\x=2\end{matrix}\right.\\ k,\left(x+2\right)\left(x+1\right)-\left(x-3\right)\left(x+2\right)=0\\ \Leftrightarrow\left(x+2\right)\left(x+1-x+3\right)=0\\ \Leftrightarrow4\left(x+2\right)=0\\ \Leftrightarrow x+2=0\\ \Leftrightarrow x=-2\\ l,\left(x-2\right)\left(x+3\right)=\left(x-2\right)\left(2x+5\right)\\ \Leftrightarrow\left(x-2\right)\left(2x+5\right)-\left(x-2\right)\left(x+3\right)=0\\ \Leftrightarrow\left(x-2\right)\left(2x+5-x-3\right)=0\\ \Leftrightarrow\left(x-2\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
\(\dfrac{\left(x+1\right)\left(x+2\right)-\left[\left(x+1\right)-x\right]}{\left(x+2\right)\left[\left(x+1\right)^2-x\right]}-\dfrac{\left(x+1\right)+2-\left(x+1\right)\left[\left(x+1\right)^3+1\right]}{\left(x+1\right)^3+1}\)
Tìm x biết :
a) \(\left(x-2\right)^3+6\left(x+1\right)^2-x^3+12=0\)
b) \(\left(x-5\right)\left(x+5\right)-\left(x+3\right)^3+3\left(x-2\right)^2=\left(x+1\right)^2-\left(x+4\right)\left(x-4\right)+3x^2\)
c) \(\left(2x+3\right)^2+\left(x-1\right)\left(x+1\right)=5\left(x+2\right)^2-\left(x-5\right)\left(x+1\right)+\left(x+4\right)^2\)
d) \(\left(1-3x\right)^2-\left(x-2\right)\left(9x+1\right)=\left(3x-4\right)\left(3x+4\right)-9\left(x+3\right)^2\)
a/ \(x=\dfrac{-5}{12}\)
b/ \(x\approx-1,9526\)
c/ \(x=\dfrac{21-i\sqrt{199}}{10}\)
d/ \(x=\dfrac{-20}{13}\)
a) (x-2)3+6(x+1)2-x3+12=0
⇒ x3-6x2+12x-8+6(x2+2x+1)-x3+12=0
⇒ x3-6x2+12x-8+6x2+12x+6-x3+12=0
⇒ 24x+10=0
⇒ 24x=-10
⇒ x=-5/12
a.
PT \(\Leftrightarrow x^3-6x^2+12x-8+6(x^2+2x+1)-x^3+12=0\)
\(\Leftrightarrow x^3-6x^2+12x-8+6x^2+12x+6-x^3+12=0\)
\(\Leftrightarrow 24x+10=0\Leftrightarrow x=\frac{-5}{12}\)
b. Bạn xem lại đề, nghiệm khá xấu không phù hợp với mức độ tổng thể của bài.
c.
PT $\Leftrightarrow (4x^2+12x+9)+(x^2-1)=5(x^2+4x+4)+(x^2-4x-5)+9(x^2+6x+9)$
$\Leftrightarrow 10x^2+42x+64=0$
$\Leftrightarrow x^2+(3x+7)^2=-15< 0$ (vô lý)
Do đó pt vô nghiệm.
d.
PT $\Leftrightarrow (1-6x+9x^2)-(9x^2-17x-2)=(9x^2-16)-9(x^2+6x+9)$
$\Leftrightarrow 11x+3=-54x-97$
$\Leftrightarrow 65x=-100$
$\Leftrightarrow x=\frac{-20}{13}$
1) \(Al\xrightarrow[]{\left(1\right)}Al_2O_3\xrightarrow[]{\left(2\right)}AlCl_3\xrightarrow[]{\left(3\right)}Al\left(OH\right)_3\)
2) \(Al\xrightarrow[]{\left(1\right)}AlCl_3\xrightarrow[]{\left(2\right)}Al\left(OH\right)_3\xrightarrow[]{\left(3\right)}Al_2O_3\)
3) \(Fe\xrightarrow[]{\left(1\right)}FeSO_4\xrightarrow[]{\left(2\right)}FeCl_2\xrightarrow[]{\left(3\right)}Fe\left(OH\right)_2\xrightarrow[]{\left(4\right)}FeO\)
4) \(Fe\left(OH\right)_2\xrightarrow[]{\left(1\right)}FeO\xrightarrow[]{\left(2\right)}FeSO_4\xrightarrow[]{\left(3\right)}FeCl_2\xrightarrow[]{\left(4\right)}Fe\left(OH\right)_2\)
5) \(Fe\xrightarrow[]{\left(1\right)}FeCl_2\xrightarrow[]{\left(2\right)}Fe\left(NO_3\right)_2\xrightarrow[]{\left(3\right)}Fe\left(OH\right)_2\xrightarrow[]{\left(4\right)}FeSO_4\)
6) \(Fe\xrightarrow[]{\left(1\right)}FeCl_3\xrightarrow[]{\left(2\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(3\right)}Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(4\right)}FeCl_3\)
7) \(Fe\left(NO_3\right)_3\xrightarrow[]{\left(1\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(2\right)}Fe_2O_3\xrightarrow[]{\left(3\right)}Fe\xrightarrow[]{\left(4\right)}FeCl_3\)
8) \(Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(1\right)}Fe\left(OH\right)_3\xrightarrow[]{\left(2\right)}Fe_2O_3\xrightarrow[]{\left(3\right)}Fe_2\left(SO_4\right)_3\xrightarrow[]{\left(4\right)}FeCl_3\)
1
1)4 Al+3O2→2Al2O3
(2)Al2O3+6HCl→2AlCl3+3H2O
(3)AlCl3+3NaOH→Al(OH)3+3NaCl
2
4Al+3O2→2Al2O3
Al2O3+6HCl→2AlCl3+3H2O
AlCl3+3NaOH→Al(OH)3+3NaCl
3
Fe+H2SO4→FeSO4+H2
(2)FeSO4+BaCl2→FeCl2+BaSO4
(3)FeCl2+2NaOH→Fe(OH)2+2NaCl
(4)Fe(OH)2→FeO+H2O
4
Fe+H2SO4→FeSO4+H2
FeSO4+BaCl2→FeCl2+BaSO4
FeCl2+2NaOH→Fe(OH)2+2NaCl
Fe(OH)2→FeO+H2O
5
Fe+2HCl→FeCl2+H2
(2)FeCl2+2AgNO3→Fe(NO3)2+2AgCl
(3)Fe(NO3)2+2NaOH→Fe(OH)2+2NaNO3
(4)Fe(OH)2+MgSO4→FeSO4+Mg(OH)2
Câu 1 :
( 1 ) 4Al + 3O2 → 2Al2O3 ( Nhiệt độ )
( 2 ) Al2O3 + 6HCl → 2AlCl3 + 3H2O
( 3 ) AlCl3 + 3NaOH → Al(OH)3 + 3NaCl
Câu 2 :
( 1 ) 2Al + 6HCl → 2AlCl3 + 3H2
( 2 ) AlCl3 + 3NaOH → Al(OH)3 + 3NaCl
( 3 ) 2Al(OH)3 → Al2O3 + 3H2O ( Nhiệt độ )
Câu 3 :
( 1 ) Fe + H2SO4 → H2 + FeSO4
( 2 ) BaCl2 + FeSO4 → FeCl2 + BaSO4
( 3 ) FeCl2 + 2NaOH → NaCl + Fe(OH)2
( 4 ) Fe(OH)2 → FeO + H2O ( Nhiệt độ )
Câu 4 :
( 1 ) Fe(OH)2 → FeO + H2O ( Nhiệt độ )
( 2 ) FeO + H2SO4 → H2O + FeSO4
( 3 ) BaCl2 + FeSO4 → FeCl2 + BaSO4
( 4 ) FeCl2 + 2NaOH → NaCl + Fe(OH)2
Câu 5 :
( 1 ) Fe + 2HCl → FeCl2 + H2
( 2 ) 2AgNO3 + FeCl2 → 2AgCl + Fe(NO3)2
( 3 ) Fe(NO3)2 + NaOH → NaNO3 + Fe(OH)2
( 4 ) H2SO4 + Fe(OH)2 → 2H2O + FeSO4
Câu 6 :
( 1 ) 3Cl2 + 2Fe → 2FeCl3 ( Nhiệt độ )
( 2 ) 3NaOH + FeCl3 → 3NaCl + Fe(OH)3
( 3 ) 3H2SO4 + 2Fe(OH)3 → Fe2(SO4)3 + 6H2O
( 4 ) 3BaCl2 + Fe2(SO4)3 → 2FeCl3 + 3BaSO4
Câu 7 :
( 1 ) 3NaOH + Fe(NO3)3 → 3NaNO3 + Fe(OH)3
( 2 ) 2Fe(OH)3 → Fe2O3 + 3H2O ( Nhiệt độ )
( 3 ) 2Al + Fe2O3 → Al2O3 + 2Fe
( 4 ) 3Cl2 + 2Fe → 2FeCl3 ( Nhiệt độ )
Câu 8 :
( 1 ) Fe2(SO4)3 + 6NaOH → 3Na2SO4 + 2Fe(OH)3
( 2 ) 2Fe(OH)3 → Fe2O3 + 3H2O ( Nhiệt độ )
( 3 ) Fe2O3 + 3H2SO4 → Fe2(SO4)3 + 3H2O
( 4 ) 3BaCl2 + Fe2(SO4)3 → 2FeCl3 + 3BaSO4
giải pt
\(\frac{2\left(x-\sqrt{2}\right)\left(x-\sqrt{3}\right)}{\left(1-\sqrt{2}\right)\left(1-\sqrt{3}\right)}+\frac{3\left(x-1\right)\left(x-\sqrt{3}\right)}{\left(\sqrt{2}-1\right)\left(\sqrt{2}-\sqrt{3}\right)}+\frac{4\left(x-1\right)\left(x-\sqrt{2}\right)}{\left(\sqrt{3}-1\right)\left(\sqrt{3}-2\right)}\)=3x-1
Câu 1 ) A / Mg(NO3) \(\underrightarrow{\left(1\right)}\) Mg(OH)2 \(\underrightarrow{\left(2\right)}\) MgCl2\(\underrightarrow{\left(3\right)}\) KCl \(\underrightarrow{\left(4\right)}\) KNO3
B/ \(Na\underrightarrow{\left(1\right)}Na_2O\underrightarrow{\left(2\right)}NaOH\underrightarrow{\left(3\right)}Na_2SO_4\underrightarrow{\left(4\right)}NaCl\underrightarrow{\left(5\right)}NaNO_3\underrightarrow{\left(6\right)}NaCl\underrightarrow{\left(7\right)}NaOH\)
C/\(Mg\underrightarrow{\left(1\right)}MgO\underrightarrow{\left(2\right)}MgCl_2\underrightarrow{\left(3\right)}Mg\left(NO_3\right)_2\underrightarrow{\left(4\right)}Mg\left(OH\right)_2\underrightarrow{\left(5\right)}MgSO_4\underrightarrow{\left(6\right)}MgCO_3\)
D/\(CuSO_4\underrightarrow{\left(1\right)}Cu\left(OH\right)_2\underrightarrow{\left(2\right)}CuO\underrightarrow{\left(3\right)}CuCl_2\underrightarrow{\left(4\right)}Cu\left(OH\right)_2\underrightarrow{\left(5\right)}CuSO_4\)
E/\(CuCl_2\underrightarrow{\left(1\right)}Cu\left(OH\right)_2\underrightarrow{\left(2\right)}CuSO_4\underrightarrow{\left(3\right)}Cu\underrightarrow{\left(4\right)}CuO\)
F/ \(Cu\left(OH\right)_2\underrightarrow{\left(1\right)}CuO\underrightarrow{\left(2\right)}CuCl_2\underrightarrow{\left(3\right)}Cu\left(NO_3\right)_2\underrightarrow{\left(4\right)}NaNO_3\)
G/\(Fe_2O_3\underrightarrow{\left(1\right)}FeCl_3\underrightarrow{\left(2\right)}Fe\left(OH\right)_3\underrightarrow{\left(3\right)}Fe_2O_3\underrightarrow{\left(4\right)}Fe_2\left(SO_4\right)_3\)
H/ \(ZnCl_2\underrightarrow{\left(1\right)}Zn\left(OH\right)_2\underrightarrow{\left(2\right)}ZnCl_2\underrightarrow{\left(3\right)}NaCl\underrightarrow{\left(4\right)}NaNO_3\)
M/\(CuO\underrightarrow{\left(1\right)}CuCl_2\underrightarrow{\left(2\right)}Cu\left(OH\right)_2\underrightarrow{\left(3\right)}CuO\underrightarrow{\left(4\right)}CuSO_4\)
N/\(Fe\left(OH\right)_2\underrightarrow{\left(1\right)}FeO\underrightarrow{\left(2\right)}FeCl_2\underrightarrow{\left(3\right)}Fe\left(ỌH_2\right)\underrightarrow{\left(4\right)}FeSO_4\underrightarrow{\left(5\right)}FeCl_2\underrightarrow{\left(6\right)}Fe\left(NO_3\right)_2\)
Z/ \(Mg\left(OH\right)_2\underrightarrow{\left(1\right)}MgO\underrightarrow{\left(2\right)}MgSO_4\underrightarrow{\left(3\right)}MgCl_2\underrightarrow{\left(4\right)}Mg\left(OH\right)_2\underrightarrow{\left(5\right)}MgCl_2\underrightarrow{\left(6\right)}Mg\left(NO_3\right)_2\)
X/\(Al\left(OH\right)_3\underrightarrow{\left(1\right)}Al_2O_3\underrightarrow{\left(2\right)}AlCl_3\underrightarrow{\left(3\right)}Al\underrightarrow{\left(4\right)}Al_2\left(SO_4\right)_3\)
g) 1. Fe2O3 + 6HCl → 2FeCl3 + 3H2O
2. FeCl3 + 3NaOH → 3NaCl + Fe(OH)3↓
3. 2Fe(OH)3 \(\underrightarrow{to}\) Fe2O3 + 3H2O
4. Fe2O3 + 3H2SO4 → Fe2(SO4)3 + 3H2O
h) 1. ZnCl2 + 2NaOH → 2NaCl + Zn(OH)2↓
2. Zn(OH)2 + 2HCl → ZnCl2 + 2H2O
3. ZnCl2 + 2NaOH → 2NaCl + Zn(OH)2↓
4. NaCl + AgNO3 → NaNO3 + AgCl↓
m) 1. CuO + 2HCl → CuCl2 + H2O
2. CuCl2 + 2NaOH → 2NaCl + Cu(OH)2↓
3. Cu(OH)2 \(\underrightarrow{to}\) CuO + H2O
4. CuO + H2SO4 → CuSO4 + H2O
d) \(^{ }4x\left(2x+3\right)-8x\left(x+4\right)\)
e) \(^{ }2x\left(5x+2\right)+\left(2x-3\right)\left(3x-1\right)\)
f) \(^{ }x\left(x+2\right)^2-\left(x+1\right)^3+3\left(x-1\right)\left(x+1\right)\)
d: Ta có: \(4x\left(2x+3\right)-8x\left(x+4\right)\)
\(=8x^2+12x-8x^2-32x\)
=-20x
e: Ta có: \(2x\left(5x+2\right)+\left(2x-3\right)\left(3x-1\right)\)
\(=10x^2+4x+6x^2-2x-9x+3\)
\(=16x^2-7x+3\)
f: Ta có: \(x\left(x+2\right)^2-\left(x+1\right)^3+3\left(x-1\right)\left(x+1\right)\)
\(=x^3+4x^2+4x-x^3-3x^2-3x-1+3x^2-3\)
\(=4x^2+x-4\)
giải phương trình
1)\(2\left(x-3\right)+1=2\left(x+1\right)-9\)
2)\(\dfrac{5-x}{2}=\dfrac{3x-4}{6}\)
3) \(\left(x-1\right)^2+\left(x+2\right)\left(x-2\right)=\left(2x+1\right)\left(x-3\right)\)
4)\(\left(x+5\right)\left(x-1\right)-\left(x+1\right)\left(x+2\right)=1\)
5) \(\dfrac{6x-1}{15}-\dfrac{x}{5}=\dfrac{2x}{3}\)
6)\(\dfrac{5\left(x-2\right)}{2}-\dfrac{x+5}{3}=1-\dfrac{4\left(x-3\right)}{5}\)
\(1,2\left(x-3\right)+1=2\left(x+1\right)-9\\ \Rightarrow2x-6+1=2x+2-9\\ \Rightarrow2x-5=2x-7\\ \Rightarrow-2=0\left(vô.lí\right)\)
\(2,\dfrac{5-x}{2}=\dfrac{3x-4}{6}\\ \Rightarrow30-6x=6x-8\\ \Rightarrow12x=38\\ \Rightarrow x=\dfrac{19}{6}\)
\(3,\left(x-1\right)^2+\left(x+2\right)\left(x-2\right)=\left(2x+1\right)\left(x-3\right)\\ \Rightarrow x^2-2x+1+x^2-4=2x^2-6x+x-3\\ \Rightarrow2x^2-2x-3=2x^2-5x-3\\ \Rightarrow3x=0\\ \Rightarrow x=0\)
\(4,\left(x+5\right)\left(x-1\right)-\left(x+1\right)\left(x+2\right)=1\\ \Rightarrow x^2+5x-x-5-x^2-2x-x-2=1\\ \\ \Rightarrow x-7=1\\ \Rightarrow x=8\)
\(5,\dfrac{6x-1}{15}-\dfrac{x}{5}=\dfrac{2x}{3}\\ \Rightarrow\dfrac{6x-1}{15}-\dfrac{3x}{15}=\dfrac{10x}{15}\\ \Rightarrow6x-1-3x=10x\\ \Rightarrow3x-1=10x\\ \Rightarrow7x=-1\\ \Rightarrow x=\dfrac{-1}{7}\)
\(6,\dfrac{5\left(x-2\right)}{2}-\dfrac{x+5}{3}=1-\dfrac{4\left(x-3\right)}{5}\\ \Rightarrow\dfrac{75\left(x-2\right)}{30}-\dfrac{10\left(x+5\right)}{30}=\dfrac{30}{30}-\dfrac{24\left(x-3\right)}{30}\\ \Rightarrow75\left(x-2\right)-10\left(x+5\right)=30-24\left(x-3\right)\\ \Rightarrow75x-150-10x-50=30-24x+72\\ \Rightarrow65x-200=102-24x\\ \Rightarrow89x=302\\ \Rightarrow x=\dfrac{320}{89}\)
BT7: Tính
\(1,A=8\left(3^2+1\right)\left(3^4+1\right)...\left(3^{16}+1\right)\)
\(2,B=\left(1-3\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)...\left(3^{16}+1\right)\)
1: A=(3^2-1)(3^2+1)(3^4+1)(3^8+1)(3^16+1)
=(3^4-1)(3^4+1)(3^8+1)(3^16+1)
=(3^8-1)(3^8+1)(3^16+1)
=(3^16-1)(3^16+1)
=3^32-1
2: B=(1-3^2)(1+3^2)*...*(1+3^16)
=(1-3^4)(1+3^4)(1+3^8)(1+3^16)
=1-3^32
1
\(A=8\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(3^{16}-1\right)\left(3^{16}+1\right)\\ =3^{32}-1\)
\(B=\left(1-3\right)\left(3+1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(1-3^2\right)\left(1+3^2\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(1-3^4\right)\left(1+3^4\right)\left(3^8+1\right)\left(3^{16}+1\right)\\ =\left(1-3^8\right)\left(1+3^8\right)\left(3^{16}+1\right)\\ =\left(1-3^{16}\right)\left(1+3^{16}\right)=1-3^{32}\)